Alternator Bolt Broke? How to Fix a Broken Alternator Mounting Bolt

Steps to fix an alternator bolt that broke

1. Remove the Alternator

   Disconnect the negative battery terminal, disconnect any electrical connectors from the alternator, remove the belt from the alternator, loosen the bolts on the alternator, and take the alternator out of the vehicle.
   
   

2. Find a Replacement Bolt or Make One

   You can find a bolt that is the same size as the alternator bolt, or you can make your own with some hand tools.
   
   Find a bolt of a length that can fit through and hold the alternator in place. If you need to, you can tighten nuts to hold the bolt in place. In this example, we tighten a locking nut, two washers, and two nuts to create a bolt that can secure the alternator. If needed, you can cut the bolt down to the necessary size.
   
   Place the bolt through the bracket to make sure it fits. Place the alternator onto the bracket and put the bolt through to confirm it fits. Inspect the bracket and bolt holes on the alternator and clean them if needed.
   
   

3. Clean the Bracket and Alternator Bolt Holes

   Spray rust penetrant into the bolt holes on the alternator and bracket to remove any debris.
   
   

4. Make a New Alternator Bolt

   With the bolt placed through the alternator and bracket, notice if there is any excess metal. When you cut the bolt, leave some extra slack but not enough to hit any other parts. Mark the position where you’d like to cut the bolt with a marker.
   
   Cut any excess metal off with a cutter. Attach two bolts at the end with the ends of two wrenches. Tighten each in different directions so they snug next to each other and won’t move. Place a washer on the end of the bolt.
   
   

5. Tighten and Torque the New Bolt to the Alternator

   Connect the bolt to the alternator and alternator bracket. Tighten the end with a locking nut. Once the bolt is secured, torque it to spec.
   
   Attach any remaining parts, like the electrical connectors and belt.